It is generally known to use an electrical device to evaporate a perfume and/or fragrance composition into a space, particularly a domestic space, e.g., a living room, to provide a pleasant aroma. There are a variety of such devices on sale, including for example the AIRWICK® Diffuser ACTIF® (manufactured by Reckitt Benckiser) or the AMBI-PUR® fragrance diffuser (manufactured by Sara Lee). Generally, these devices consist of a perfume or fragrance source, an electrical heater, and a power supply. By the application of heat to the perfume or fragrance source, there will be a continuous supply of the perfume or fragrance to the space in which the device is placed.
The problem with this arrangement is that a person occupying the space will quickly become accustomed to the perfume or fragrance and, after a while, will not perceive the fragrance strength as being as intense, and may not notice it at all. This is a well-known phenomenon called habituation. A solution to this problem has been sought.
One effort to deal with this problem is described in U.S. Patent Application Publication No. US 2002/0159916 A1, to Whitby et al. The Whitby et al. patent application discloses a method and device adapted to provide to a space, two or more fragrance compositions, at least one of which fragrance compositions is provided periodically. The method and device may provide a continuous supply of a first fragrance composition and a periodic supply of a second fragrance composition. The fragrance composition(s) may be vaporized by heating and may include deodorant and/or insecticidal compounds. The fragrance compositions are preferably chosen such that the two fragrance compositions contrast with one another or have different notes. The fragrance composition is generally pulsed from a device which includes a heater. The periodic supply of heat to release the fragrance composition is controlled by providing the device, and particularly the heater, with a controller. The controller is in the form of an electronic circuit. The controller is arranged such that the heater runs for a short period of time, preferably from 15 seconds to 15 minutes with “appropriate intervals of time there between.”
The Whitby et al. patent application, however, appears to be directed primarily to maintaining or sustaining the olfactory impact of the fragrance composition being emitted continuously, rather than to providing to the user noticeable changes in fragrances. In addition, although the Whitby et al. patent application mentions periodic supply of two or more fragrances, there is no specific teaching of emission patterns or programs dictating the supply of the different fragrances relative to each other so that the users actually experience distinct fragrances rather than one fragrance, which is a blend of the two compositions.